A 60-year-old man has been treated for a T2N0M0 squamous-cell carcinoma by radical radiotherapy. He has a history of chronic alcoholism and was a heavy smoker. Six years after treatment, he develops a painful ulcer in the alveolar mucosa in the treated area following minor trauma. His pain worsens and the bone became progressively exposed. He is treated by a partial mandibular resection with graft.
- What diagnosis is most likely?
The features suggest osteoradionecrosis. Recurrent carcinoma is possible but less likely.
- How does radiotherapy damage tissues and what structural features might be seen in the bone?
Radiotherapy damages tissues by producing free radicals. DNA damage may prevent cell division and repair. Endoarteritis obliterans results in reduced vascular supply to the tissues. Bone may become necrotic, showing osteocyte death, sequestration and breakdown of the matrix. Infection may result in osteomyelitis
- What changes may arise in irradiated connective tissues 10 years after exposure?
Mutations and other genetic damage may lead to neoplasia in irradiated tissues. Osteosarcoma can arise in this way.